Geog3561Lab05_F09 - Geography 3561/5561 Fall 2009 Lab5: Due...

Geography 3561/5561 – Fall 2009Lab 5: Satellite Image ClassificationDue: In your lab session, Oct. 20th, 21st, 22nd, 26thINSTRUCTIONSComplete the lab exercises described below. When you have worked through the lab, answer the questions that appear at the end of this document. Make sure to enter your name and lab section in the space provided. Print your answers and turn them in by the start of lab next week. INTRODUCTIONIt is now common practice to classify satellite images to produce land cover maps of large regions. Various classification techniques exist for assigning a land cover class to each grid cell in a satellite image, but the most efficient techniques inevitably misclassify many of the grid cells in an image. It is possible to verify the accuracy of particular cells by “ground truthing” or by examining high-resolution aerial photos.LEARNING OBJECTIVESUntil this point, you have mostly worked with vector spatial data in ArcView GIS. In this lab assignment, you will begin working with raster spatial data within Idrisi—a GIS that is designed primarily for raster spatial data analysis. You will use Idrisi to apply spatial sampling and create and analyze classification error matrices, an important standard technique for spatial data quality assessment.Upon completion of this lab assignment, you should understand:1.Basic knowledge in using Idrisi.2.How to combine bands into composite imagery.3.How to classify satellite images with unsupervised classification.4.The necessity for calculating thematic accuracy of data sets through sampling.5.How to interpret an error matrix to evaluate classification quality. EXERCISESA) Setup1.First, set up some disk space for your work on this lab. If you have not already created a personal working folder (C:\temp\[UofM ID]) on your computer, do so now. Then, create a new working folder for this lab entitled lab05 inside of C:\temp\[UofM ID] and copy all of the files in G:\Geog 3561\lab05 into that new folder.

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2.Open Idrisi Taiga through the start menu and set up a “project environment”:•From the File menu, select Idrisi Explorer.•Right-click inside the Projects tab, and select “New Project”.•Navigate to your temporary working directory in the Browse for folder dialog and click OK. •Make your new project is highlighted selected. Click on it if it’s not.Now that you have specified a “main working folder,” Idrisi will use this folder as the default location to save files and to look for files to open. If you move your files to a different computer, you’ll need to repeat these steps to define the project folder.

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